Screening machine and vibrating hammer therefor



H. K. NAJARIAN SCREENING MACHINE AND VIBRATING HAMMER THEREFOR Filed Aug. 10, 1923 5 Sheets-Sheet 1 SCREENING MACHINE AND VIBRATING HAMMER THEREFOR Filed Aug. 10, 19 23 3 Sheets-Sheet H. K. NAJARlAN SCREENING MACHINE AND VIBRATING HAMMER THEREFOR Filed Aug. 10 1923 3 Sheets-Sheet 5 Patented Nov. 4, 1924.

. UNITED. STATES HERAND K. NAJ'ARIAN, OF BONNE TERRE, MISSOURI.

SCREENING MACHINE AND VIBRATING HAMMER THEREFOR.

Application filed August 10, 1923. Serial No. 656,680.

To all whom it may concern:

Be it known that I, HERAND 'K. NAJARIAN, a citizen of the United States, residing at Bonne Terre, county of St. Francois, and State of Missouri, have invented certain new and useful Improvements in Screening Machines and Vibrating Hammers Therefor; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, referencebeing had to the accompanying drawings, and t0 the char actors of reference marked thereon, which form a' art of this specification.

This lnvention relates to a screening or .sifting machine for the separation, into more uniformly sized products, of comminuted'materials such as crushed rock and ore, sand, gravel, coal and coke, flour, fertilizer, and analogous substances.

The'method of screening I employ is to let the material to be screened run downwards over the surface of an inclinely spaced screen, while said screen is being rapidly vibrated, the fine particles in the said material passing through the openings and going to the undersize and the coarse particles traveling downwardsover said screen and passing to the oversize.

My machine essentially consists of an inclinely placed screen frame carrying a screen and yieldingly and resiliently supported on springs from a rigid machine frame, a v1- brating hammer suspended on yielding wooden'arms and supported from said machine frame, and a transmitter, one end of which is connected to said screen and screen frame and the other cooperating with the and upwardly from its initial position of rest, the path of said vibrations being practically normal to the general plane of said screen.

The action of the upward vibrations on whereby) from the surface of the screen this process facilitating the passage of the liner particles through the openings in the screen. The action of the downward vibrations is such that particles of material clogging the apertures in the screen are dislodged therefrom at each downward vibration thus keeping the screening surface at its maximum efficiency.

Inmy machine the force necessaryfor vibrating the screen as hereinbefore described is obtained by the rapid change of momentum of the heavy vibrating hammer, vi-

brating during operation, in a closed nonlipeal path, as more fully describedhereina ter.

For a more complete explanation of my screening machine and vibrating hammer, reference willbe had to the accompanying drawings, in which:

Fig. 1 is a longitudinal section showing the vibrating hammer and the transmitter in section and in their normal inoperative position.

Fig. 2 is a cross-section on line 22, Fig. 1, showing the ring portion of the transmitter, section of nose shaft and roller toggle, and an end view of the lower portion of said transmitter.

Fig. 3 is a vertical cross-section of my screening machine on line 33, Fig. 4.

Fig. 4 is a front view and partial section of my machine, the sectional part bein taken on line 44, Fig. 3.

ig. 5 is a cross-section of the vibrating hammer, taken on line 5-5, Fig. 1.

Fig. 6 is a diagram illustrating the method vibration is produced in the transmitter y means of change in the path of vibration of the vibrating hammer.

The same reference characters will be used to designate the same several views.

I will first describe the construction and the operation of thevibrating hammer. Referring to Figs. 1 and 5, the vibrating hammer consists of a cylindrical casing 1, which I term vibrator casing, made of suitable material such as cast-iron or steel and for purposes of construction made with varyin thicknessees of metal and varying inside and outside diameters throughout its length; a

removable endoover 2 having a central opening and fastened to one end of said vibrator casing by means of screws 3; a nose shaft 4 at the opposite end of said vibrator casing,

parts throughoutthe one portion of said nose shaft being secu-rely inserted into the end of the vibrator casing and the remainder projecting outwards from said vibrator casing; hollow wings 5 (Figs. 3, 4 and 5) on the outside periphery of said vibrator casing, serving as receptacles for yieldin arms 6; a drive shaft 7 one portion of whic is within the'said vibrator casing and the remainder'protruding out through the. central opening in the end cover 2 and carrying a drive pulley 8, the portion within the vibrator casing) being journaled in bearings 9, one of said inside of said vibrator casing and the other securely held inside the end cover; an unbalanced disc 10 mounted securely on said portion of said drive shaft within the vibrator casing and intermediate the bearings thereof.

The unbalanced disc 10 comprises a metal disc, referably circular in section, bored centra ly to receive the drive shaft 7 and portions of the disc so cut out as to make it unbalanced with respect tothe center-line of said drive shaft. The cavities formed by cutting out portions of said disc are filled -with a much lighter material than the material of the disc and carefully smoothed over to make it suitable to run in oil "continuousl In Figs. 1 and 5, plug 11 represent t e portions of the-unbalanced disc filled with wood. The nut 12 is screwed to one end of the drive shaft 7 and against the hearing, held in vibrator casing, and a bushing 13 is pressed against the bearing held in the end cover 2, thus preventing undue sidewise movement of bearings 9. To reduce friction'in the machine, I employ rolleror ball bearings and fill the vibrator casing half full of oil to keep said bearings well lubricated, the packing ring 14 being used to seal I the opening between the outside periphery of the drive shaft and the central opening 1n the end cover 2.

For the purpose of explanation, I will designate the whole vibrating hammer by the reference number 15 (Figs. 3 and 4). The yielding arms 6, which pass through the hollow win s 5 of the vibrating hammer 15, are refera ly made of wood and are held at t eir extremities in pillow blocks 16, which are in turn rigidly fastened to the projecting portions of the rigid machine frame 17.

When the drive pulley 8 is rapidly rotated, the unbalanced centrifugal force created within the unbalanced disc 10 is transmitted through the bearings 9 to the vibrator casing and as the yielding arms are free to bend in any direction, the entire vibrating hammer 15 vibrates in the'path of a distorted ellipse. I call this path the orbit of vibration of the vibrating hammer. This orbit is determined by the, magnitude of the unbalanced centrifugal force, the weight of earings securely held the vibrating hammer and the flexibility of the yielding arms. For the purpose of transmitting the v1- brating force from the vibrating hammer 15 to the screen frame 18 and screen 19, I employ a transmitter 20 (Figs. 1, 2, 3 and 4), one end of said transmitter being flanged and rigidly connected to bracket 23, which is in turn rigidly connected to said screen frame 18. The other end of the transmitter is designed to cooperate with the vibrating hammer as follows: 5

Referring to Figs. 1 and 2, on the protruding portion of the nose shaft 4 is mounted a roller 21, bored to fit rotatably on said protruding portion of the nose shaft. The outside periphery of the roller is made circular in cross-section and in its normal inoperative position does not touch any part of the transmitter. Theoretically, it is not essential that the roller shall not touch the transmitter while inoperative and I do not want to confine myself to the construction shown, but for the proper operation of the machine for the purposes that it is used, I prefer to have'a space left between the cooperating surfaces of the roller and the transmitter, as fully explained hereinafter. The ring portion of the upper .end of the transmitter 20 is bored .to receive a removable ring 22 snugly fitted so that it will not turn when the machine is in operation. The inside periphery of ring 22 is so designed that when the vibrating ham mer is in operation, one or more portions of said inside surface cooperates with the roller toggle 21 while other portions of said surface do nottouch the roller toggle, This is done to transmit force through the transmitter at any desired direction according to the requirements of the. machine.

In my screening machine, I have found that the best results are obtained when the screen is vibrated twice during each complete cycle of vibration of the vibrating hammer, or alternately downwards and upwards, hereinbefore mentioned. Consequently, I make the inside surface of the ring 22 sothat there are two oppositely placed surfaces adapted to cooperate "with the roller toggle 21. by boring the inside of ring 22 oblong, making the diameter of the ring on axis X-X much larger than the diameter on axis Y-Y. The transmitteris so placed tha axis Y Y is substantially normal to the general plane of the screen and-the screen frame. Thus the surfaces on the inside of ring 22, which are at the extremities of its short axis Y--Y, are closer to the outside circular periphery of the roller toggle 21 than the remainder of said inside surface and during operation the transmitter vibrates alternately in the directions of arrows M and N. 1 The distances between This is accomplished theseaforementioned surfaces, represented in- Fig.42by a and b are governed by therequirem'ents of the machine, usually made one sixty-fourth to one thirty-second of an inch. The distances represented by c and ".d are made so that the roller will not come in contact with them during operation. In practice I have found that the distances 0 and 03 each should be slightly larger than one-half the average diameter of orbit of'vibration of the vibrating hammer. Thus, if the weight and the 'speed of the vibrating hammer are so proportioned that it vibrates in an orbit of about one-fourth of an inch in diameter,

the distances 0 andfd are made slightly greater than one-eighth of an inch.

Referring to Fig. 6, let broken line 24 represent the orbit of vibration, of the vibrating hammer in a very much enlarged form. Let 25 represent the roller and assume that the mass of the vibrating hammer is concentrated in the roller. Let 26 represent one ofthe inside cooperating surfaces in ring 22. Assuming that the roller toggle is traveling on its orbit 24 in the direction of the arrow 27 when said roller meets the surface 26, a reactionary force,

roller diverting said roller from its orbit 24 to a new orbit representedby dot-and dash line 29. The reactionary force is due mainly to the resistance of the springs and also to the weight of parts vibrated. The force in the roller acting against this surface 26 is equal in magnitude and opposite in direction to the reactionary force represented by; arrow 28. The new orbit of vibration is shorter in circumference and as the weight of the vibrating hammer is constant and the time oftone complete vibration is also constant, the result is retarda tion in velocity and lessening in momentum of the vibrating hammer. This change in'momentum is entirely dependent on the reactionary force that can come against the surface of the roller from the cooperating surface-inside the ring 22. The force eaerted against the surface 26' from the roller 25 is equal to force 28 and opposite in direction, said force acting against the force of the springs will move said surface 26 from its position 30 to position 31 during the vupward travel of the roller in its orbit and as the roller travels downward to; 0-.

\ sition 32, said surface follows and reac es its original position, thus completing one vibration of the transmitter. Hence, the

number of such cooperating surfaces in,

surfaces properly, I provide a cover 33 for the open end of the transmitter ring, said cover being fastened to the transmitter ring by screws 34 and provided with a central Oll hole 35,- and an oil hole cover 36.

The side edges 37 of the screen 19 are turned upwards to act as bafiles to prevent coarse material going to the undersize. The screen frame 18 is fastened to the springs 38 by mcansof bolts 39, said bolts holding said screen frame and said spring rigidly together through lugs .40 on the screen frame and lugs 41 fastened to the springs. The springs are rigidly fastened. to the projecting angles 42 of the machine frame 17.

I do not want to confinemyself to the specific construction details shown herein, as different screening problems require specific details to be incorporated in the construction of the machine.

Having now describedmy invention, what I claim as new is:

'1. In a screening machine comprising a support, a vibrating hammer yieldine'ly supported from said support and vibrating in a {closed nonlineal path during operation, a single roller rotatably mountedon said vibratlng hammer and vibrating therewith, a screen carried on a screen frame andter rigidly connected to said screen frame" and screen, a ring forming a part of said transmitter and having one or more portions of its'inside surface adapted to come in contact with said roller a given number of times during a rotation of said rollers, thereby causing change in momentum of the vibrating hammer and generating force which vibrates said transmitter and said screen in the direction of said force.

2. In a screening machine, a transmitter, one end of which is flanged and adapted to be secured to a screen frame, the other end comprising a cylindrical ring, portions of the inside surfaces of said ring so distanced from its centerline as to make parts of said ring surfaces at a shorter distance from the centerline of said ring than othersfthereby affording surfaces to 'co-operate with the outer surfaces of-a single roller rotatably mounted on 'a vibrating hammer when in operation and thereby causing a vibratory force to be generated acting normal to the cooperating surfaces thereof. I

3. "A- vibrating hammer" comprising a oylindrical casing, a removable end cover at IIO one'end of said casing with a central opening, a removable nose shaft securely inserted at the other end ofsaid casing, part of said '9 Ill nose shaft projecting from said end of the casing, a roller rotatably mounted on a proecting portion of the nose shaft, an unbalanced disc within said casing and mounted on 'a drive shaft, one portion of said drive shaft jouinaled within the casing 'on two bearings carrying the unbalanced disc interinediatethe said bearings, and the other end of said drive shaft protruding out through the central opening in end cover and carrying a drive pulley and hollow wings on the outside periphery of said casing for the reception ofyielding arms.

4. A vibrating hammer comprising a casing having an. axial opemng extending therethrough, a bearing secured in said opening, a cap removably secured to the end of thecasing, a second bearing secured in said cap, an unbalanced discmounted on the shaft intermediate the said bearings a drive pulle on the end ofthe-drive shaft a second shaft secured to the casing and projecting from the same, and a transmitter member provided with an opening for the- 1 reception of the last named shaft.

5. A vibrating hammer comprising a. casing, a cylindrical portion projectingfrom' one end of said casing, a cap closing. the other end of said casing, a pair of bearin s supported in the casing, a shaft rotatably mounted in said bearings, an unbalanced inghaving an axial chamber of substantially circular cross-section, one end of said chain:

' ber being of smaller diameter than the other, a shaft having one end secured in said opening of reduced diameter. and having the other end projecting outwardly from the casing, a roller mounted on the projecting.

portion of said shaft, a cap secured to sai casing and adapted .to close the other end thereof, a bearing secured in the casing, a second bearing secured to the cap, a shaft rotatably' mounted in; said bearings, a circular disc having a central opening adapted to be non-rotatably mounted on said shaft,

said disc being heavieron one side than on the other, means for yieldingly supporting said casing, and means for rotating sai shaft and disc at a high rate of speedfwh'erely circular cross-section, one end ofusaid' chamber being of smaller diameter than, the other, a shaft having one end secured in said opcningof reduced diameter and having the other-end projecting outwardly from the casing, a roller mounted on the projecting portion of said shaft, a cap secured to said casing and adapted to close the other end thereof, a bearing secured in the casing, a second bearing secured to the cap, a shaft rotatably mounted in said bearings a circular dischaving a central opening a a ted to be non-rotatablymounted on said sha t, said disc being heavier on one side than on'the other means for yieldingly supportin said casing, means for rotating said sha t and disc at a high rate of speed whereby the roller will vibrate in a closed curve, and a" transmitter having one end provided withv a non-circular opening adapted-to receive said roller. and to cooperate therewith.

8. A- vibrating hammer com rising a casing having an axial chamber o substantially circular cross section, one end of said chamber being of. smaller diameter than the other,

a shaft having one end securedin said open-'.

ing of" reduced diameter and having the other *end' projecting outwardly from, the

casing, a roller mounted on the projectin portion of said shaft, a cap secured to said casing and adapted to close the'othe'r end thereof, a bearing secured in the casing} second bearing secured to the cap, a shaft rotatably mounted in said bearings, .a circular disc on sa'id'last named shaft, said disc having a central opening adapted to receive the shaft, portions of said i v out unsymmetrical to the. axis thereof, said out out portionsibeing filled with a lighter a.

means for yieldinglysu-pporting said Casi-n and means for rotatingsaid shaftfand:

1sk being cut material so as to make thedisk unbalanced, i ino 

